Packages containing materials for use in blasting operations



March 22, 1960 I. o. LEWIS 2,929,325

PACKAGES CONTAINING MATERIALS FOR USE IN BLASTING OPERATIONS FIG I FiledNov. 21. 1955 INVENTOR IDWAL OWEN LEWIS TORNEYS 2,929,325 PACKAGESCONTAINING MATERIALS FOR USE IN BLASTING OPERATIONS Idwal Owen Lewis,Ardrossan, Scotland, assignor to Imperial Chemical Industries Limited,London, England, a corporation of Great Britain Application November 21,1955, Serial No. 548,212

Claims priority, application Great Britain February 25, 1955 9 Claims; c102-24) The present invention relates to the production and applicationof packages of materials suitable for use in blasting operations.

, The explosive compositions employed for blasting operations areconventionally produced by mixing the ingredients together and packagingthe resulting mixture as such in a container which, according to thenature of'the explosive mixture and the situation in which it isrequired to be used, may be a thin paper wrapper, which may or may notbe waxed, or a'more substantial waterproof structure of a pliable orrigid construction, .for example a rubberised cloth bag or a tinplatecanister. More than 80 years ago, however, Sprengel proposed that thereshould be used for blasting operations explosive mixtures made up fromindividually non-explosive constituents which were to be separatelytransported to the scene of the blasting operation and brought togetherinto contact there for the first time. This practice would have obviousadvantages as regards safety in storage and transport of the materialsrequired and consequently in the cost of their carriage. Sprengeldescribed three methods by which what have come to be known as Sprengelexplosives could be made up.

Briefly, Sprengels three methods consisted in mixing at the scene of theblast either a liquid non-explosive oxidising agent with a liquidnon-explosive fuel or with a solid non-explosive fuel, or a liquidnon-explosive fuel with a solid non-explosive oxidising agent. Incertain countries the operation of bringing together non-explosiveoxidising agents and non-explosive fuels at the scene of the blast is anoperation that can only be carried out in accordance with conditionslaid down in enactments relating to explosives, but this does notdetract from the advantages to be gained in respect of the cost ofstorage and transport of the non-explosive ingredientsto the place wherethis operation isto be conducted. The solid non-explosive oxidisingagents specified by Sprengel were the chlorates and perchlorates of thealkali metals and alkaline earth metals and the nitrates of the alkalimetals and alkaline earthmetals which are not hygroscopic. The liquidfuels he suggested included carbon 3 bisulphide, intro-benzene, alcoholsand oils, and the liquid oxidising agents suggested by him wereoxy-acids,. particularly nitric acid. The liquid oxygen explosives ofcommerce and those chlorate explosives in which a stick or the like ofpotassium chlorate is dipped in an oil at the scene of theiblast areobviously in accordance with the principles enunciated by Sprengel.Sprengel stated that the mixing in this way of solid non-explosiveoxidising agents and solid non-explosive combustible agents had beentried and abandoned as impracticable.

It does not appear to have occurred toSprengel that in the production ofan explosive whose ingredients were to be mixed on the spot thatammonium nitrate'would pre-. sent certain advantages over the chlorate,perchlorates and nitrates of I the alkali and alkaline earth metals.Whenunmixed with self-explosive sensitisers: or .with

2,929,325 Patented Mar. 22,

2 organic or inorganic fuels, ammonium nitrate is a compound that canonly be caused to detonate with consider able difficulty, and inpractice ammonium nitrate unmixed with other ingredients may be storedand transported otherwise than as an explosive. Although in the greatmajority of the ammonium nitrate explosive of commerce the compositioncontains a self-explosive ingredient of an oxidisable nature, or aself-explosive ingredient and an oxidisable ingredient which can beoxidised by the ammonium nitrate, it is nevertheless possible to preparecompositions made up from ammonium nitrate and solid fuels alone withoutintroducing any self-explosive ingredient as a sensitiser for theammonium nitrate, which will propagate their own detonation providedthey are used in charges of sufficient diameter and are sufficientlyprimed. In producing such compositions the ammonium nitrate has usuallybeen brought into very intimate admixture with the solid fuel, forinstance by grinding them together or by a wet impregnation technique. I

The present invention. depends on the fact that it is possible toproduce exposive charges of sufficient capacity for commercial blastingoperations by simple shaking together of separate charges consistingrespectivelyzat least predominantly of dry ammonium nitrate particlesand of particles of a solid fuel devoid of explosive constituents andconsisting for example at least predominatingly of dried vegetabletissue carbonaceous material, which may if desired or if necessaryinclude as a minor constituent particles of a metal oxidisable bytheammonium nitrate and known to be capable of increasing thesensitivity'ofammonium nitrate explosives devoid of self-explosiveconstituents, the amount of said solid fuel being sufiicient to'providean at least approximately oxygen balanced mixture, for instance anaccurate oxygen balanced mixture or one having an oxygen deficiency orexcess not exceeding 5% of that theoretically required to provide steam,carbon dioxide and nitrogen as the gaseous products of its selfcombustion.

Thus, the invention has for its principal object the provision of anovel package arrangement containing materials for use in blastingoperations, and also the provision of a novel process for preparing anexplosive composition which comprises initially preparing the novelpackage arrangement, referred to.

Further objects and advantages of the invention will be in part obviousand in part pointed out hereinafter.

The novel features of' the invention may be best'm'ade clear from thefollowingdescription and accompanying drawings in which:

Figure 1 is a longitudinal section view through a pack age arrangementembodying the invention; and 7 Figure 2 is a longitudinal sectional viewthrough another form of package arrangement embodying the invention. r a1 A package according to the invention consists of a substantiallycylindrical waterproof container of greater length than diameterenclosing two non-explosive charges kept apart from one another by aninternal separation;v wherein one charge consists at least predominantlyof. ammonium nitrate particles and the other charge consists ofparticles of a solid fuel, as forinstance one which'com-.

' prises dried vegetable tissue carbonaceous material, sufficient inamount to provide an at least approximately oxygen balanced mixture withthe first mentioned charge, wherein the volume of said containerslightly exceeds that of the combined bulk of said charges, and whereinthe separation continues to serve as such until it is purposelyvegetable piths, cereal meals, comminuted cereal husks' adhesive tape.whenever -'it*is -pierced it tends to split so as to permit it -itorspring back towards the cylindrical .wall, :and *thflsopensupa-communication .betweenrthe twp compartand straws, ccmrninuted p a andlign co l nd anthracite dusts. The state of division of the ammoniumnitrate and of the dried vegetable tissue carbonaceous materialinfluences the sensitiveness of the resulting mixture and its capacityfor propagating its own detonation, which also depend on the internaldiameter of the container. Depending on the degree of sensitiveness toinitiation and propagation required for the cartridge, e.g. whether itis required to be effective with a detonator alone or whether a boosterexplosive cartridge will be present to prime it, and on the state ofdivision of the particles of the ammonium nitrate and the driedvegetable tissue carbonaceous material, it may be necessary to includein the fuel particles a metal powder capable of acting as a sensitiser.For this purpose aluminium is very effective especially if at least aportion of the aluminium is in the paint fine state of division.

The body of the waterproof container is advantageously somewhat rigidand it may be made of metal, plastic or'stout waxed paper. One suitableform of construction of the container is in the form of a cylindricalcup with a detachable substantially cylindrical lid also in the form ofa cup, the internal separation between the ammonium nitrate particlesand the fuel particles being provided by enclosing either the ammoniumnitrate particles or preferably the fuel particles in a closed internalcontainer, for instance of rubber or plastic or textile coatedtherewith, which is removed by the operator after he has removed the.lid of the outer container, and whereof the contents are spilled by himinto the outer container, the lid of the outer .container then replaced,and the container with its contents thereafter shaken or tumbled inorder to mix the ammonium nitrate with the fuel particles. .Such a formof construction of the cartridge is illustrated in .Fig. 1 wherein 1 isa waxed paper cylindrical cup closed at its lower end; 2 is a lid .ofsimilar material capable of being pushed over the open end of thecontainer for a considerable distance; 3 is a strip of adhesive servingto maintain a waterproof joint. Occupying the greater portion of thevolume of the inner cup is the charge of loose ammonium nitrateparticles and a rubber bag 4 situated above the charge 5 and containingthe charge 6 of the fuel particles, comprising the dried vegetabletissue carbonaceous material.

When the contents of the cartridge are to be mixed the waterproof tape 3is unwound, cup 2 is removed, bag 4 is opened and its contents arepoured into cup 1. Cup 2 is replacedand the contents are shaken ortumbled together. It is arranged that there is still some free spaceunoccupied by the ammonium nitrate and the fuel particles during themixing operation so as to permit this to be carried out effectively.After mixing has been completed, cup 2 is brought down over cup 1 as faras it will go so as to minimise the unoccupied space of the contents ofthe cartridge. If the cartridge is to be stored the tape mayconveniently be replaced.

In another form of the invention the container body is in the .form of acup completely separated by a septum of a soft .elastic material, forinstance rubber, in a state of tension, into :a compartment containingpreferably the ammonium nitrate particles and a compartment containingthesolid fuel particles and a cup-shaped lid which has a piercer'memberprojecting from the interior surface of its closed end towards saidseptum, the container body having a stop member attached externally toit, normally -'in position to abut the open end of the lid to hold thepierceroutof contact'with said'septum, said stop member beinghowevercapable of manual removal by the operator to :permit the .piercer to beadvanced forcibly on to and through said septum. The stop member may befor example a tightly fitting yrubber band or a wrapping of As theseptum is in a state of tension,

is ments of the closed container wide enough to permit effective mixingof the ammonium nitrate and the fuel when the still closed container isshaken or tumbled.

An embodiment of this form of the invention is illustrated in Fig. 2,wherein the numbers 1, 2, 5 and 6 have the same significance as inFig. 1. In Fig. 2, 9 is a pin attached to the cup 2 and projectingaxially with its point towards a thin rubber membrane 10 stretched overthe mouth of the cup 2. A stout rubber ring 7 stretches round a portionof the cylindrical surface of the cup 1 and provides a stop for the cup2 and thus prevents the pin 9 from puncturing the rubber cup 2 until theoperator removes a rubber tape seal 8 and forcibly retracts the ring 7towards the bottom of the cup 1.

When this has been done the cup 2 can be forced further on to the cup 1so as to cause the pin 9 to pierce the rubber cup 10, which immediatelytends to break up and to form an effective communication for mixing thecharges when the cartridge is shaken by the operator. The joint betweencups 1 and 2 is not so tight as to prevent the air at the top of cup 2from escaping between the two cups when cup 2 is brought down.

The sensitiveness of the resulting explosive composition is improved thefiner is the grist size of the am,- monium nitrate, and the higher isthe specific surface of the solid fuel, e.g. the higher is the specificsurface of the vegetable tissue carbonaceous material.

For a container having an internal diameter exceeding about 5" it willusually be possible to obtain compositions capable of propagating theirdetonation effectively under the influence of a booster cartridge fromammonium nitrate and the vegetable tissue carbonaceous material alone.By however including aluminium particles, whereof at least a portion isin a paint fine state of division, amongst the fuel particles there canbe produced mixtures which will be sensitive to initiation by commercialdetonators and will propagate their detonation satisfactorily even indiameters down to 2" or even less.

Thus, when there is used ammonium nitrate ground in an attrition milluntil 100% passes a 100 B5. screen, 85% passes a 170 B5. screen andpasses a 240 ES. screen in one compartment of the cartridge and fuelconsisting of dry vegetable tissue carbonaceous materials and aluminiumin the other compartment of the cartridge, and these are shaken togetherat the scene of the blasting operations the resulting mixtures aresensitive to No. 6 commercial detonators, and propagate their detonationin 4 oz. cartridges of 1%" diameter when the propagations are such as toproduce mixtures of the following compositions.

If a package according to the invention is 2" in diameter and 6" longand contains as one charge ammonium nitrate of ,such grist size that100% passes a 36 BS. screen, passes a 30 BS. screen and 30% passes a3.8. screen and as the other charge afuel consisting of a mixture ofcork dust, ground charcoal and paint fine aluminium, wherein therelative proportions of the ammonium nitrate and the three ingredientsof the fuel are such that when the two charges are mixed together bygiving the package a few shakes after modifying the separation betweenthe charges for it no longer to act in this way an e plo v m xt o th folowi compositiom is formed and thus a blasting cartridge which issensitive to a No. 6 commercial lead azide detonator and which has apower of 80% of blasting gelatine.

What I claim is: 1. A package comprising two non-explosive charges, oneof said charges consisting predominantly of ammo.- nium nitrateparticles and the other of said charges being particles of a solid fuelin an amount suflicient to provide a substantially oxygen balancedmixture with the first mentioned charge, a waterproof container of sheetmaterial enclosing said charges, said container being of a volume whichslightly exceeds the combined bulk of said charges, separating meanswithin said container for maintaining said charges initially separateone from the other,

said separating means being removable whereby mixing by removingsaid'separating means and shaking said container.

2. A package as claimed in claim 1 wherein said particles of a solidfuel comprise dried vegetable tissue carbonaceous material.

3. A package as claimed in claim 1 wherein said particles of a solidfuel include a metal powder capable of acting as a sensitiser.

4. A package as claimed in claim 3 wherein the metal powder is aluminiumat. least a portion of which is in a paint fine state of sub-division.

5. A package as claimed in claim 1 wherein the body of the waterproofcontainer is made of metal.

6. A package as claimed in claim 1 wherein the sepa ration between theammonium nitrate particles and the fuel particles is provided byenclosing the fuel particles in a closed internal container.

7. A package as claimed in claim 1 wherein the internal separation is a"septum of soft elastic material in a,

state of tension.

' anced mixture with said. first charge; maintaining said chargesseparated until said explosive composition is to be used and thenremoving said separating member and mixing said charges by shaking saidpackage to form said explosive composition.

9. The process of claim 8 wherein said charges are 1 kept separateduntil said package is positioned adjacent vof said charges within thecontainer may be accomplished the point where said composition is to beused.

References Cited in the file of this patent UNITED STATES PATENTS 5France Feb. '18, 1953

1. A PACKAGE COMPRISING TWO NON-EXPLOSIVE CHARGES, ONE OF SAID CHARGESCONSISTING PREDOMINANTLY OF AMMONIUM NITRATE PARTICLES AND THE OTHER OFSAID CHARGES BEING PARTICLES OF A SOLID FUEL IN AN AMOUNT SUFFICIENT TOPROVIDE A SUBSTANTIALLY OXYGEN BALANCED MIXTURE WITH THE FIRST MENTIONEDCHARGE, A WATERPROOF CONTAINER OF SHEET MATERIAL ENCLOSING SAID CHARGES,SAID CONTAINER BEING OF A VOLUME WHICH SLIGHTLY EXCEEDS THE COMBINEDBULK OF SAID CHARGES, SEPARATING MEANS WITHIN SAID CONTAINER FOR MAINTAINING SAID CHARGES INITIALLY SEPARATE ONE FROM THE OTHER, SAIDSEPARATING MEANS BEING REMOVABLE WHEREBY MIXING OF SAID CHARGES WITHINTHE CONTAINER MAY BE ACCOMPLISHED BY REMOVING SAID SEPARATING MEANS ANDSHAKING SAID CONTAINER.